What is compression?
Compression is a way of making data smaller so it takes up less space or can be sent faster. It works by finding patterns or redundancies in the information and representing them in a more efficient form.
Let's break it down
Think of a long sentence that repeats the word “apple” many times: “apple apple apple apple apple”. Instead of writing it out each time, you could say “apple x5”. Compression does something similar with files - it looks for repeated bits, unused space, or predictable sequences and replaces them with shorter codes.
Why does it matter?
Smaller files mean you can store more on your phone, computer, or cloud storage. They also travel faster over the internet, which speeds up downloads, streaming, and website loading. In addition, less data uses less bandwidth, which can lower costs for businesses and users.
Where is it used?
- Images (JPEG, PNG) and videos (MP4, H.264) to reduce file size while keeping visual quality.
- Audio files (MP3, AAC) to shrink music and podcasts.
- Documents and archives (ZIP, RAR) for sending multiple files together.
- Web pages (GZIP, Brotli) to make websites load quicker.
- Mobile apps and games to keep download sizes small.
Good things about it
- Saves storage space and reduces costs.
- Speeds up data transfer and improves user experience.
- Enables streaming of high‑quality media over limited bandwidth.
- Makes backups and archives more manageable.
- Often transparent to users - you open a compressed file and it works like the original.
Not-so-good things
- Some compression (lossy) permanently removes data, which can lower quality (e.g., blurry images).
- Compressing and decompressing takes CPU time, which can slow down devices with limited power.
- Over‑compression can cause files to become corrupted if the algorithm isn’t robust.
- Not all data compresses well; already compressed files may not shrink much and can even grow slightly.